1. Field of the Invention
This invention relates generally to photo-optical keyboard apparatus and more specifically to the concept of utilizing a single photo-optical component as both a light generator and light detector in a matrix array for use, for example, in a keyboard.
2. Description of the Prior Art
The vast majority of presently available photo-optical keyboard constructions utilize multiple light generators and multiple light detectors. Usually, these components are arranged in rows and columns with the light generators disposed at the row positions and the light detectors disposed at the column positions or vice versa depending on the designer's choice.
This multiplicity of component assemblies is not only expensive but also complicated to assemble, maintain and operate as a result of the miniaturization involved. In addition, the printed wiring boards which are required for such apparatus are also expensive to produce due to the complex circuitry employed with the multiplicity of component assemblies.